An epoxy resin composition is provided including at least the following component [A], component [B], and component [C] or [D] wherein cured product obtained by curing the epoxy resin composition has a rubbery state modulus in dynamic viscoelasticity evaluation of 10 MPa or less, and the cured product has a glass transition temperature of at least 95° C.; [A] an aromatic epoxy resin having a functionality of at least 3, [B] an aromatic diamine having a substituent at ortho position of each amino group or a cycloalkyldiamine wherein the carbon atom adjacent to the carbon atom bonded to each amino group has a substituent, [C] an aliphatic polyamine having an alkylene glycol structure, [D] a straight chain or branched aliphatic polyamine containing 6 to 12 carbon atoms.